February 2023: 1st discussions for the possibility and creation of a SAR-21 AEG.
April 2023: Start of the SAR-21 AEG project 
real weapon infos : (SAR-21 not to be confused with the Israeli CTAR-21)
The SAR-21 is a bullpup assault rifle from ST Kinetics/Engineering.
Chambered in 5.56x45 NATO, introduced in 1999, it equips the Singapore Army (SAF).
The majority of the platform is polymer and ST Kinetics offers a multitude of variations (see below). 
The first model that will be modeled is the SAR21 MMS in the "Carbine" version: 680mm long, a "Triple rail picatinny" handguard, short barrel, an upper picatinny (which may recall the Aug A3) etc.
Before modeling, we will have to collect as many photos as possible, from all angles of the platform (and yes, this cannot be improvised) .
I will therefore spend several hours viewing, analyzing photos and videos etc.
I particularly thank B. who was able to provide me with a certain number of photos.
We can then attack the modeling, which will take the longest.
In particular, it will be necessary to define internal compatibility, mag compatibility, and many other parameters, etc. (and that too cannot be improvised)
June 2023:
First renderings, and first pieces to print.
First rendering of the full replica: 
The Upper and Handguard part is going to be printed, while the Lower still requires some attention.
Here is the result : 
Parts compatible the first time, so no need for correction.
We will be able to start prototyping the largest parts of the replica: the Lower.
The Lower is 3 pieces made up of the buttstock, and the 2 body portions.
This is the most critical part since it accommodates the pneumatic assembly of the AEG replicas (Gearbox, Block hop-hup, mosfet etc).
August/September 2023:
During the summer, I will be prototyping and improving the Lower/Stock group of the replica.
I will also take the opportunity to model the SAR21 LWC, which consists of a different upper/handguard assembly.
The Lower remains unchanged, which makes the different handguards compatible with the same and unique lower. (same principle as an AR15 and the multi-configs of upper)
This applies to the majority of variants of the SAR21 which will be produced over time.
Here the SAR21 LWC: 
September/October 2023:
1st problem, the gb does not fit correctly in the Buttstock piece, i have to go back through the modeling part to correct that.
Not being at my first barbecue, I correct it and it goes back into print.
October/November 2023:
A lot of work.
Blanking
The stock was reworked and revised for ease of disassembly, reassembly in case of maintenance.
The lower also with an improvement of its security system.
The upper remains unchanged.
The butt and its implantation with the Gearbox shows a problem.... QD locations
It is therefore necessary to replace the QD locations on the lower to avoid constraints on the buttstocck.
We can finally see the total length and compare with other models.
Here is a comparison with my VHS-K2 AEG (700mm).
The Length of Pull of the SAR 21 is +/- identical to vhs (in buttstock short position)
let's continue with the cheek riser
Buttstock Modifications
Added a dummy fire selector, and geometry improving of the butt.
December 2023 :
To be Continued...